Question: Add. $28+11+ 34 + 17=$
First, let's add $28 + 11$. $$ $$ $$ $$ ${+}$ $$ $$ ${=}$ $$ $$ $$ $$ $$ $28} + {11} = 39$ Now, let's add $39$ to $34$. $$ $$ $$ $$ $$ ${+}$ $$ $$ $$ $$ ${=}$ $$ $$ $$ $$ $$ $$ $$ $$ $39 + {34} = 73$ Last, let's add $73$ to $17$. $$ $$ $$ $$ $$ $$ $$ $$ ${+}$ $$ $$ $$ ${=}$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $73+ {17} = 90$ $28+11 + 34 + 17= 90$